The invention relates to a rotary-latch lock, of which the rotary latch has a fork mouth for accommodating a mating locking part which, in the locked position of the lock, is located in front of a blocking flank formed by a fork-mouth leg, having a window-like opening which promotes plastic deformation when the blocking flank is subjected to increased loading.
A rotary-latch lock of the type in question is known from DE A 28 03 351, which rotary-latch lock is used for the releasable locking of a backrest of a vehicle seat. The window-like opening of the relevant fork-mouth leg is configured as a loading-relief bore and provided beneath a run-on slope in the fork-mouth leg. This makes it possible to form between the loading-release bore and the run-on slope, in the event of a crash, a plastically deformable region which prevents the rotary latch from sliding off from the mating locking part. On account of the particular bore-like outline of the window-like opening, largely controlled plastic deformation takes place, to be precise in the region where the spacing is smallest between the bore and the run-on slope and/or the corresponding section of the blocking flank. In the case of this configuration, however, it is not possible to avoid the situation where stress peaks occur on the rotary latch under increased loading, which is the case, for example, in the event of a crash, it being possible for said stress peaks, in some circumstances, to result in the rotary latch breaking, to be precise in the region of the rotary-latch weak point formed by the fork mouth.
The object of the invention is to configure a rotary-latch lock of the generic type such that even high loading forces acting on the rotary latch do not result in any functional incapability of the rotary latch.
This object is achieved with a rotary-latch lock having the features of the introductory-mentioned paragraph, wherein the opening forms a bending/extending web.
The following subject matter of the invention may be important alone or in combination with the above-mentioned independent features of the invention.
Such a configuration provides a rotary-latch lock of the generic type which has an increased safety value. The opening which forms a bending/extending web results in compensation for stress peaks in the event of a crash and/or under increased loading and reliably avoids the risk of the relevant fork-mouth leg tearing or breaking. This means that the functional capability of the rotary-latch lock is maintained even following a crash. This is important, in particular, if the rotary-latch lock is assigned to vehicle doors which, once the vehicle has been involved in a crash or accident, have to be opened in order for it to be possible for any injured individuals to be rescued quickly. The essential plastic deformation in the event of a crash takes place in the region of the bending/extending web. Deliberately controlled deformation is thus realized. An advantageous variant of the invention is distinguished in that the bending/extending web runs parallel to the blocking flank. Accordingly, the essential plastic deformation is assigned to the rotary latch. The slot configuration of the window-like opening compensates for installation tolerances, with the result that the effectiveness which is sought after according to the invention is not impaired. The essential plastic deformation in the event of a crash takes place in the region between the slot and the blocking flank. The rest of the rotary latch is subjected to a lower level of deformation. At the same time, it is possible, overall, for the relevant fork-mouth leg to warp to a certain extent without this resulting in the material of the rotary latch tearing. Furthermore, the bending/extending web may be part of the bearing eyelet for the rotary bearing of the rotary latch and/or catch. Even then, the bending/extending web can run parallel, to be precise concentrically in relation to the relevant articulation pin. In addition, it is also possible for the bending/extending web to be arranged parallel to the blocking flank. Provision is then made for the stresses which occur under the increased loading in the region of the fork-mouth root to be reduced as a result of the opening extending into the fork-mouth root. The region of the rotary latch, which is thus very much at risk, is reliably protected as a result. Emphasis should also be given to the fact that the length of the web is considerably greater than the diameter of the mating locking part and of the bearing eyelet. This greater length is available for warping in the event of a crash, with the stress peaks which occur in this case being reduced in the process. It proves to be optimal if the mating locking part or the articulation pin, which engages through the bearing eyelet, butts approximately centrally against the web. In order largely to eliminate stress peaks which occur in the region of the fork-mouth root, the opening section which is assigned to the fork-mouth root follows the curvature of the blocking flank and/or of the bearing eyelet. A further advantageous feature is that the window width corresponds approximately to half the diameter or the radius of the mating locking part and bearing eyelet. Under increased loading, accordingly, the bending of the bending/extending web is not adversely affected to any significant extent. Variations in the dissipation of stress peaks may be realized in that the rotary latch and/or the catch, in particular the opening, are/is sheathed in plastic. It is possible here for the opening to contain a compressible plastic filling. The bending deformation is additionally controlled by this plastic filling. Production-related advantages are achieved in that the plastic filling is configured integrally with the sheathing. This configuration is varied, furthermore, in that the plastic filling has webs which form cavities. These webs may be oriented in different ways. A zigzag arrangement of the webs is also recommended.
A number of exemplary embodiments of the invention are explained hereinbelow with reference to the drawings, in which: